109 research outputs found

    Photocatalytic performance of textiles coated with titanium dioxide-reduced graphene oxide system for degradation of crude petroleum under similar solar irradiation

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    The pollution caused by oil and its toxic derivatives presents a considerable risk to the public health and the environment. This work is devoted to the study of the influence of TiO2 nanoparticles immobilized on three types of textiles materials (Cotton, Entretela, and Polylactic Acid-PLA) coated with reduced graphene oxide (RGO) to be used for degradation of crude petroleum under simulated solar irradiation. The morphological studies of the functionalized textiles substrates were performed by using Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy, which indicated an excellent dispersion and adhesion of nanoparticles of about 60% (atomic %Ti) on the textile fibers covered with RGO after washing. Ultraviolet-visible Diffuse Reflectance spectra suggest a reduction in the band gap energy of TiO2 up to 2.86 eV due to the presence of RGO. The functionalized textiles presented at least 60% of photocatalytic efficiency measured by Rhodamine B degradation, decreasing less than 12% after the rigorous washing. The excitation/emission Synchronous Fluorescence Spectroscopy and Fourier-transform Infrared spectroscopies demonstrated a great potential for photocatalytic degradation of the functionalized textiles substrates as the appearance of the hydroxyl, carboxyl, and the C-O bands confirm the photoinduced oxidation of the organic compounds implying with high prospects in petroleum and wastewater treatment areas. Moreover, this environmentally friendly, sustainable, and inclusive research work can be included in clean technologies, contributing to the novel socio-economic model recognized as "Green Recovery".[GRAPHICS].This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019 and the project PTDC/FIS-MAC/6606/2020. Also, the third author would like to acknowledge the FCT for the Ph.D. scholarship (SFRH/BD/137421/2018). Moreover, the authors would like to acknowledge Sociedade Nacional de Combusti ' veis de Angola (Sonangol), which partially provided the crude oil samples

    Bioclimatic characterization of outdoor and confined systems for pregnant sows

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    O confinamento de matrizes suínas foi criado com o intuito de maximizar a produtividade; entretanto, existem problemas relacionados ao bem-estar animal. Objetivou-se avaliar a criação de matrizes suínas gestantes no sistema de confinamento e ao ar livre, com relação ao ambiente térmico e às respostas fisiológicas. O experimento foi realizado em Monte Mor/SP. A avaliação fisiológica foi realizada por meio do registro das variáveis: frequência respiratória e temperatura de pele. Foram registradas as variáveis meteorológicas: temperatura de bulbo seco, temperatura de bulbo úmido e temperatura de globo negro, caracterizando o ambiente por meio da entalpia e índice de temperatura de globo e umidade. Foram utilizados seis animais por tratamento. O delineamento experimental foi inteiramente casualizado em parcelas subdivididas, e as médias comparadas pelo teste de Tukey. As variáveis fisiológicas e meteorológicas apresentaram valores superiores no confinamento. O sistema de criação ao ar livre potencializou as trocas térmicas entre os animais e o ambiente, o que refletiu em menor estresse por calor observado nos animais

    Coaxial fibres incorporated with phase change materials for thermoregulation applications

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    Nowadays, the growing concern about improving thermal comfort in different structures (textiles, buildings, and pavements, among others) has stimulated research into phase change materials (PCMs). The direct incorporation of PCMs into composite materials can cause mechanical impacts. Therefore, this study focuses on the design of phase change coaxial fibres (PCFs), using commercial cellulose acetate (CA) or recycled CA obtained from cotton fabrics (CAt) as the sheath and polyethylene glycol (PEG) 2000 as the core, via the wet spinning method; the fibres vary in molecular weight, concentration and ejection velocity. The fibres were assessed for their optical, chemical, thermal, and mechanical properties. The presence of PEG2000 is confirmed in the core of the fibres. Thermal analyses revealed a mass loss at high temperatures, attributable to the presence of PEG2000. Notably, the fibres with CA (Mn 30,000) showed superior thermal and mechanical performance. The melting point of PEG2000 incorporated into these PCFs coincided with the melting point of pure PEG2000 (about 55 °C), with a slight deviation, indicating that PCFs were obtained. Finally, the results point to the application of the fibres in civil engineering materials requiring a phase change between 50 and 60 °C, providing promising prospects for their use in applications requiring thermoregulatory properties.This research was funded by the Portuguese Foundation for Science and Technology (FCT) under the projects MicroCoolPav EXPL/EQUEQU/1110/2021 and NanoAir PTDC/FISMAC/6606/2020 (https://doi.org/10.54499/PTDC/FIS-MAC/6606/2020) and within the framework of Strategic Funding UIDB/04650/2020, UIDB/04029/2020 (https://doi.org/10.54499/UIDB/04029/2020) and UID/QUI/0686/2020. I.R.S. and H.P.F. would like to thank FCT for their funding contracts 2022.00763.CEECIND (https://doi.org/10.54499/2022.00763.CEECIND/CP1718/CT0006) and 2021.02720.CEECIND (https://doi.org/10.54499/DL57/2016/CP1377/CT0098)

    Prevention of hypertension in patients with pre-hypertension: protocol for the PREVER-prevention trial

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    <p>Abstract</p> <p>Background</p> <p>Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage.</p> <p>Methods</p> <p>This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution.</p> <p>Discussion</p> <p>The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil.</p> <p>Trial Registration</p> <p>Clinical Trials <a href="http://www.clinicaltrials.gov/ct2/show/NCT00970931">NCT00970931</a>.</p
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